1. Field of the Invention
The present invention is related to the field of animal containment and, more particularly, to a system and method for defining a wireless dog fence that surrounds a user-defined area and for using the fence to contain one or more dogs within the user-defined area.
2. Description of the Related Art
Containing one or more dogs within a prescribed area has been achieved in many different ways, most traditionally through the construction of a fenced enclosure that is high enough to prevent the dog from escaping the enclosure by going over the fence. Since some consider above-ground fencing to be unattractive or otherwise undesirable, “invisible” fence products have been developed that rely on a wire buried underground that defines a desired “fence” border for the dog or dogs. The wire transmits a signal that activates a specially designed collar worn by the dog when the dog comes within a certain proximity of the border. The collar, once activated, can issue an audible warning and/or an electric shock to the dog to ensure that the dog does not leave the “fenced-in” area. Buried wire systems are labor intensive to install. Further, since the wire may be unintentionally cut, or otherwise damaged, such as by digging or tilling during lawn maintenance or the like, such buried wire fence systems are also labor intensive when attempting to find the location of the broken wire or other difficulty.
More recently, wireless fence products have been developed that radiate a low frequency signal to saturate a spherical volume which translates to a generally circular area on the ground plane. The radius of the circle is user-definable and, according to one such product manufactured by PetSafe, generally extends radially from about 5 feet to about 90 feet. When the dog, while wearing a specially designed collar, is “inside” the signal saturated area, the collar receives a signal and no action is taken. When the dog moves outside the signal area, however, the collar delivers a correction signal.
Another wireless system is that marketed by Perimeter Technologies, Inc. which, rather than creating a signal-saturated area, uses a distance measuring technology between the collar and a base unit to determine the range of the dog from the base unit. However, interference created by objects often found within a household environment can cause the collar and base to lose communication with one another, resulting in undesired corrections being delivered to the dog, i.e., corrections when the animal is within the defined containment radius. In addition, the Perimeter Technologies system is also limited to a generally radial or circular area which does not allow the user to make allowance for specific geographic or other individualized aspects of the area within which the dog is to be contained.
In view of the desirability of a custom-shaped fence, U.S. Pat. No. 7,259,718 (“the '718 patent”) discloses an electronic pet fence that allows the user to establish a desired boundary having a user-defined shape. Using a master and two slave transceivers arranged in a triangular configuration, the master transceiver communicates with the slaves and records round trip travel times for radio signals between the collar and each of the transceivers. A logic device at the master transceiver uses these round trip times to determine the location of the collar using triangulation or trilateration. However, in a household setting, problems often arise with signal attenuation and signal loss such that one of the transceivers may, at any given time, be out of communication with the collar. This results in the inability to locate the collar and often the issuance of an inappropriate correction to the dog. Furthermore, the '718 patent provides no means of preventing fence border irregularities caused by signal attenuation during set up, and also lacks any ability to identify and ignore erroneous collar location data collected while the system is in use. Such erroneous data, if not detected for what it is, can also result in unwanted corrections being issued to the dog.
Accordingly, a need exists for an improved wireless fencing system that is easy for the consumer to set up and use and that overcomes the problems encountered with prior art systems.